Magnetic disk drive

ABSTRACT

A magnetic disk drive comprises a plurality of disks that have a laminated arrangement with equally fixed spaces respectively and are rotatably mounted a disk driving unit that forces the disks to rotate, a plurality of positioners mounted and movable in the direction of the tracks of the disks respectively, a positioner driving unit that drives the positioners so that their respective ends can traverse the tracks, and a plurality of reproducing/recording elements e.g., unitary magnetic heads that are fixed on the respective ends of the positioners and perform read/write operations for the surfaces of recording media of the disks, respectively. Each of the unitary magnetic heads is constructed such that each of said heads has a predetermined inclination is to the respectively corresponding surface of recording media of the disks, preferably by forming a sloping surface on one end of each positioner. 
     Preferably, circuits for controlling the disk driving unit and the magnetic head, etc., of a disk drive are composed of a flexible printed circuit board to be contained in the disk enclosure having a base and cover.

This is a continuation of application(s) Ser. No. 08/299,241 filed onAug. 31, 1994, now U.S. Pat. No. 5,572,388, which is a continuation ofSer. No. 07/895,681 filed on Jun. 8, 1992, now abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a magnetic disk drive that can beutilized as an external memory of a computer. More specifically, itrelates to an electromagnetic read/write structure of a magnetic diskdrive including at least one magnetic disk, the corresponding magnetichead, and the like. Further, it relates to the arrangement of variouscomponents of a magnetic disk drive within a disk enclosure.

2. Description of the Related Art

Generally, a magnetic disk drive, having a number of magnetic disksutilized as recording media, has been in practical use in variousregions including computer networks as one of the promising non-volatilememory devices. Furthermore, in recent years, the fabrication of amagnetic disk drive that satisfies the demand for a disk drive that iscompatible, compact, inexpensive, has a large storage capacity, is lightweight and has lower power consumption, has been required and has beenin demand.

To meet the above requirements, it is necessary for as many magneticdisks as possible to be assembled in a confined space, rather thanincreasing the surface density of recording media of magnetic disks byimproving the characteristics of the magnetic head, magnetic medium perse, etc., so that mass storage can be attained without increasing costsfor the development of the improved magnetic head. Also, even when manydisks are assembled in the space, it is necessary for the size of thedisk drive to be reduced as small as possible, so that effective spacecan be saved thereby promoting compactibility. When the magnetic diskdrive is applied to a mobile-type computer, such as a portable lap-toppersonal computer, it also becomes necessary for the disk drive towithstand external impulse and external electromagnetic disturbance, andbe lighter in weight and have a lower power consumption.

In a known magnetic disk drive according to the prior art, typically, anumber of disks are arranged rotatably at high speed in a laminatedmanner with equally divided spaces and on the respective surfaces of themagnetic layers, recording media are formed concentrically. Further, inthe vicinity of these disks, positioners are mounted and movable in thedirection of the tracks of the disks, respectively, and supportingmembers are attached to the above positioners, respectively. Further, onthe respective ends of the above supporting members, thereproducing/recording elements, e.g., magnetic heads are fixed in closeproximity to the respective surfaces of the disks, so that the formercan perform read/write operations for the tracks of the disks.

To be more specific, each of the above supporting members have an armthat is fixed on each of the positioners. The base end portion of eachsuspension element is fastened to the tip portion of each arm withscrews. The above suspension element is formed by a bending process ofan extremely thin stainless steel sheet. Further, on both sides of, thesuspension element, bent portions are formed respectively to ensure thestiffness of the above suspension element. Each magnetic head isattached to the tip portion of each suspension element, via a gimbal.

In such a construction of a magnetic disk drive, in order to increasethe maximum sheets of disks that can be assembled in a given placewithin a disk enclosure, it seems reasonable that the thickness of thearms of supporting members should be decreased so that the distancebetween the surfaces of adjoining disks become shorter. However, whenthe above distance is too short, the bent portions of adjoiningsuspension elements are likely to interface and come into contact witheach other. Therefore, it is difficult for the distance between thesurfaces of adjoining disks to be reduced below a fixed value.Furthermore, since the thickness of each magnetic head or any otherportion of a supporting member other than the bent portion is alsonecessitated to some degree, it becomes more difficult for the distancebetween the surfaces of adjoining disks to be reduced to a value lessthan the limited value (for example, 3 mm). Consequently, when thedimensions of the disk drive are predetermined, a disadvantage occurs inthat the sheets of disks cannot be increased much more than the limitedvalue known in the prior art. On the contrary, when the number of sheetsof disks assembled are predetermined, another disadvantage occurs inthat the thickness of the disk drive cannot be reduced less than thelimited value also known in the prior art.

Furthermore, in the conventional 5 inch, 3.5 inch or 2.5 inch magneticdisk drive, a printed board of various controlling circuits is usuallypositioned separately from the disk enclosure including the magnetichead, disks, etc. Typically, the above printed board is fixed on thebottom surface of the disk enclosure, i.e., outside the disk enclosure(for example, see U.S. Pat. No. 5025335 (Frederick M. Stefansky)).Therefore, taking into account the thickness of the printed board, theheight of the whole disk drive becomes more significant (for example,approximately 15 mm). Consequently, because of the thickness of theprinted circuit board, it is further difficult to promote compactibilityin the disk drive.

Further, last year a 1.8 inch disk drive was introduced by IntegralPheripherals Inc. The construction of the above disk drive is similar tothat of other disk drives and the height of the former disk drive isalso approximately 15 mm as a whole. Integral Pheripherals Inc. isfurther emphasizing that a thinner disk drive, as thin as 10 mm, can berealized by locating a printed circuit board on the side of a diskenclosure. In this case, though the thickness of the disk drive can bereduced, a new problem occurs in that the area of the disk driveincluding the printed circuit board and the disk enclosure is enlargedmore than usual.

SUMMARY OF THE INVENTION

Accordingly, an object of the present invention is to provide a diskdrive having a magnetic head supporting structure that enables thedistance between the surfaces of adjoining disks (the thickness of spacebetween the disks) to be reduced as small as possible, to realizesimultaneously, smaller dimensions, compactibity, higher storagedensity, larger storage capacity, lower cost, higher performance and thelike.

A further object of the present invention is to provide a disk drivehaving a whole structure that enables a printed circuit board to becontained in a disk enclosure, to realize smaller dimensions both inthickness and area.

A still further object of the present invention is to provide a diskdrive having a whole structure that is lighter in weight and higher inrigidity.

An additional object of the present invention is to provide a disk drivehaving plural magnetic heads and a supporting structure thereof, inwhich read/write operations can be performed at a higher speed and withsmaller dimensions (e.g., less than 2.5 inch).

To attain the above objects, the disk drive according to the presentinvention has the following components: one or more disks that have alaminated arrangement with equally fixed spaces respectively and aremounted rotatably, a disk driving means that forces said disks torotate, one or more positioners mounted and movable in the normaldirection of the tracks of the disks, respectively, a, positionerdriving means that drives the positioners so that their respective endscan traverse the tracks, and one or more reproducing/recording elementsthat are fixed on the respective ends of the positioners and performread/write operations for the surfaces of recording media of the disks,respectively. Further, each of the reproducing/recording elements isconstructed such that each has a predetermined inclination to therespectively corresponding surface of recording media of the disks.

Preferably, each of the above reproducing/recording elements is aunitary magnetic head consisting of a flexible thin sheet body, a headportion that is located on one tip portion of the body and has an airgap for reproducing or recording on one surface of the body, and amounting portion formed on the opposite tip portion of the body.Further, in this case, on each of the ends of the positioners is formeda sloping surface that has a given inclination to the respectivelycorresponding surface of recording media of the disks, and wherein saidmounting portion is constructed to be fixed on the corresponding slopingsurface.

Further preferably, on the upper side and lower side of one end of eachpositioner, sloping surfaces are formed respectively, and the mountingportions of a pair of unitary magnetic heads are fixed on the upper andlower side of one end of each positioner, respectively.

Further preferably, one end of each of the positioners is divided intotwo branches, and the first and second sloping surface portions areformed on a respective end position of the branches, on which the firstunitary magnetic head unit and second unitary magnetic head unit arefixed respectively, so that the first and second unitary magnetic headunits can perform read/write operations for the internal peripheral partand the external peripheral part of the tracks of each disk,respectively.

In such a construction, a read/write operation at each disk can beperformed simultaneously by means of a plurality of unitary magneticheads, and therefore the read/write operation can be executed at ahigher speed, which leads to the shortening of access time necessary forthe completion of a sequence of read/write operations.

Further, in a preferred embodiment, the above first and second unitarymagnetic head units further comprise pairs of unitary magnetic headportions, respectively. Namely, four unitary magnetic heads are arrangedin each of the positioners.

Further preferably, in each of the positioners is fixed one or more armsthat extend toward the corresponding surface of a recording medium ofeach of the disks, and each of the unitary magnetic heads is arranged onone tip portion of the arm, supporting the unitary magnetic head.

Further, in another preferred embodiment, at least one arm portionfunctioning as the above arms is integrated with each of the positionersas a portion thereof.

Further, in another preferred embodiment, a disk drive according to thepresent invention includes the following components: one or more disks,a disk driving means that forces the disks to rotate, one or morereproducing/recording elements that perform read/write operations forthe surface of a recording medium of the disk, one or more arms thatsupport the reproducing/recording elements, one or more positioners thatsupport the arm rotatably, one or more bearings that are arranged toallow the positioner to rotate, a positioner driving means that forcesthe positioner to rotate and make the reproducing/recording means moveto a predetermined position on the surface of a recording medium of thedisk, and a base and cover that constitute a disk enclosure incombination with each other. In this case, the above disk enclosureprotects the main part of the above-mentioned various components.

Further, in another preferred embodiment, a disk drive according to thepresent invention includes the following components: two disks having adiameter of less than 1.8 inch, a disk driving means that forces thedisks to rotate, four magnetic heads that perform read/write operationsfor the surfaces of recording media of the disks, arms that support themagnetic heads, positioners that support the arms rotatably, bearingsthat are arranged to allow the positioners to rotate, a positionerdriving means that forces the positioners to rotate and make magneticheads move to a predetermined position on the surface of recording mediaof the disks, a base and cover that constitute a disk enclosure incombination with each other, and circuits for controlling at least thedisk driving means, read/write operations of the magnetic heads and thepositioner driving means. In this case, the above circuits are composedof a flexible printed circuit board to be contained in the diskenclosure, and consequently the height of the magnetic disk drive isless than 10.5 mm.

Further preferably, the flexible unitary magnetic head described beforeis used as the above magnetic head. In this case, the storage capacityof the disk drive can become greater than 120 MByte.

BRIEF DESCRIPTION OF THE DRAWINGS

The above object and features of the present invention will be moreapparent from the following description of the preferred embodimentswith reference to the accompanying drawings, wherein:

FIG. 1 is a top view of a magnetic head supporting structure for a diskdrive according to a prior art;

FIG. 2 is a front view of the magnetic head supporting structure of FIG.1;

FIG. 3 is a front view of a portion of a magnetic disk drive, includingthe magnetic head support structure shown in FIG. 1;

FIG. 4 is a simplified front view of a portion of a disk drive made inaccordance with a first preferred embodiment of the present invention;

FIG. 5 is a top view of a larger portion of the magnetic disk drive ofFIG. 4, made according to the present invention;

FIG. 6 is a front view of the part of the magnetic disk drive shown inFIG. 5;

FIG. 7 is an enlarged front view of a unitary magnetic head used in theapparatus of FIGS. 5 and 6;

FIG. 8 is an enlarged internal view of the unitary magnetic head shownin FIG. 7;

FIG. 9 is an enlarged sectional view taken along lines 9--9 of FIG. 5;

FIG. 10 is a top view of a magnetic disk drive made according to a firstpreferred embodiment of the present invention;

FIG. 11 is a front sectional view of the magnetic disk drive of FIG. 10,taken along lines 11--11 in FIG. 10;

FIG. 12 is a partial sectional top view of a first example of anarrangement of lead wires for the unitary magnetic head in FIGS. 5 and6, taken along lines 12-13, 12-13 in FIG. 6;

FIG. 13 is a partial sectional top view of a second example of anarrangement of lead wires for the unitary magnetic head in FIGS. 5 and6, taken along lines 12-13, 12-13 in FIG. 6;

FIG. 14 is a top view of a second preferred embodiment of a magneticdisk drive made according to the present invention;

FIG. 15 is a front sectional view of the apparatus of FIG. 14, takenalong lines 15--15 in FIG. 14;

FIG. 16 is a top view of a portion of a third preferred embodiment of amagnetic disk drive made according to the present invention;

FIG. 17 is a front view of the apparatus of FIG. 16;

FIG. 18 is a top view of a magnetic disk drive made according to thethird preferred embodiment of the present invention;

FIG. 19 is a sectional view of the apparatus shown in FIG. 18, takenalong lines 19--19 in FIG. 18;

FIG. 20 is an enlarged sectional view taken along lines 20--20 of FIG.16;

FIG. 21 is a partial sectional view of a portion of a disk drive madeaccording to a fourth preferred embodiment of the present invention;

FIG. 22 is a top view of the apparatus of FIG. 21;

FIG. 23 is a front view of a fifth preferred embodiment of a portion ofa disk drive made according to the present invention;

FIG. 24 is a front view of a sixth preferred embodiment of a portion ofa disk drive made according to the present invention;

FIG. 25 is a simplified front view of a portion of a seventh preferredembodiment of a disk drive made according to the present invention;

FIG. 26 is a top view of a portion of a magnetic disk drive madeaccording to the seventh preferred embodiment of the present invention;

FIG. 27 is a front view of the apparatus shown in FIG. 26;

FIG. 28 is an enlarged perspective view of a portion C of the apparatusof FIG. 27;

FIG. 29 is a top view of a portion of a magnetic disk drive madeaccording to an eighth preferred embodiment of the present invention;

FIG. 30 is a front view of the apparatus of FIG. 29;

FIG. 31 is an enlarged perspective view of a portion D of FIG. 30;

FIG. 32 is a top view of a ninth preferred embodiment of a disk drivemade according to the present invention;

FIG. 33 is a top view of a portion of a magnetic disk drive madeaccording to a tenth preferred embodiment of the present invention;

FIG. 34 is a front view of the apparatus of FIG. 33;

FIG. 35 is an enlarged perspective view of a portion E of FIG. 34;

FIG. 36 is an internal view of a disk drive in which two disks areassembled in a disk enclosure according to the present invention;

FIG. 37 is an exploded perspective view of a portion of the apparatus ofFIG. 36;

FIG. 38 is a perspective view of a portion of the apparatus of FIG. 36partially assembled; and

FIG. 39 is an enlarged perspective view of a portion of the apparatusshown in FIG. 36.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Before describing the embodiments of the present invention, the relateddisadvantages will be described with reference to-the related figures.

FIGS. 1, 2 and 3 are views showing a disk drive having a magnetic headsupporting structure according to a prior art. To be more specific, FIG.1 is a top view showing the magnetic head supporting structure and FIG.2 is a front view showing the magnetic head supporting structure andFIG. 3 is a front view showing the main part of the magnetic disk driveincluding the magnetic head supporting structure. In this case,positioners that support arms are omitted to simplify the explanation.

In these figures, an arm 1, which is fixed on each of the positionersand driven by each positioner so that the arm 1 can traverse the trackof the corresponding disk 7, is provided for each disk. Further, a baseend portion of each suspension element 3 is fastened to the tip portionof each arm 1, via a spacer 2, with screws 4. In this case, the abovesuspension element is formed by bending an extremely thin stainlesssteel sheet to form the main part of a supporting member. Here, thespacer 2 is utilized as reinforcing material for the suspension element3. Further, on both sides of the suspension element 3, bent portions 3aare formed respectively to ensure the stiffness of the above suspensionelement. Further, each reproducing/recording element, e.g., magnetichead 6 is attached to the tip end portion of each suspension element 3,via gimbal 5 functioning as a part of the supporting members. Further,as shown particularly in FIG. 3, a number of disks 7 are arrangedrotatably with high speed in a laminated manner with equally dividedspaces respectively. Each magnetic head 6 is fixed in close proximity tothe surface of the corresponding disk 7, so that the former can performdata read/write operations for the track of each disk.

In such a magnetic disk drive construction according to the above priorart, in order to increase the maximum sheets of disks 7 that can beassembled in a given place within a disk enclosure (not shown in FIGS.1, 2 and 3), it appears reasonable that the thickness of arms 1 shouldbe decreased so that the distance between the surfaces of adjoiningdisks 7 become shorter. However, when the above distance is too short,the bent portions 3a of adjoining suspension elements 3 are likely tointerface and come into contact with each other. Therefore, it isdifficult for the distance between the surfaces of adjoining disks to bereduced below a fixed value. Furthermore, since the thickness of eachmagnetic head 6 and spacer 2, etc., are also restricted to some degree,it becomes more difficult for the distance between the surfaces ofadjoining disks to be reduced to a value less than the limited value(for example, 3 mm). Consequently, when the thickness of a disk drive ispredetermined, the prior art shown in FIGS. 1, 2 and 3 has adisadvantage in that the sheets of disks 7 cannot be increased much morethan the limited value. On the contrary, when the number of sheets ofdisks 7 assembled are predetermined (for example, one or two sheets ofdisks), the conventional disk drive has another disadvantage in that thethickness of the disk drive cannot be reduced less than the limitedvalue, since the space within a disk enclosure cannot be utilizedeffectively.

FIGS. 4 to 11 are views showing a first preferred embodiment of a diskdrive according to the present invention. To be more specific, FIG. 4 isa simplified front view showing the characteristics of the presentinvention; FIG. 5 is a top view showing the main part of the magneticdisk drive; FIG. 6 is a front view of FIG. 5; FIG. 7 is an enlargedfront view showing a unitary magnetic head of FIG. 6; FIG. 8 is anenlarged sectional view showing a unitary magnetic head of FIG. 7; FIG.9 is an enlarged sectional view taking along 9--9 of FIG. 5; FIG. 10 isa top view showing the whole structure of the magnetic disk drive andFIG. 11 is a front view of FIG. 10. In some of FIGS. 4 to 11,positioners 14 are partially omitted to simplify the drawings.

First, the whole structure of a preferred embodiment of the presentinvention will be explained with reference to FIGS. 4 to 11. In thesefigures, 11 denotes a base of the magnetic disk drive. On this base 11,plural sheets of disks (in FIG. 11, three sheets of disks areillustrated) are rotatably arranged in a laminated manner. These pluralsheets of disks 13 are constructed to be driven rotatably at a highspeed (for example, 3600 r.p.m.) by a spindle motor, which isrepresentative of a disk driving means not shown in these figures.

Further in these figures, 14 denotes positioners that are mountedrotatably on a base 11 and movable in the direction of the tracks of thedisks 13 respectively, so that the respective ends of the positionerscan traverse the tracks.

A coil 15 is provided on the respective rotatable opposite ends of thepositioners 14. More specifically, the above coil 15 is arranged insidethe magnetic gap of a magnetic circuit 16 that is formed on the base 11.In this case, when an electric current is supplied to the above coil 15,a driving force is induced in the coil 15 and then a VCM (voice coilmotor), which comprises the above coil 15, forces the positioners 14 torotate. Thus the coil 15 operates as a positioner driving means.

Further, in the positioners 14, a plurality of arms (in FIG. 11, fourarms) 17 that extend toward the respectively corresponding surfaces ofrecording media of disks 13 are fixed. To be more concrete, the arms 17are arranged in a laminated manner around a rotational axis of thepositioners 14. On one tip portion of the arms 17 are arrangedreproducing/recording elements that perform data read/write operationsfor the surfaces of recording media of the disks, respectively.

Next, the above reproducing/recording elements will be explained in moredetail, with reference to FIGS. 4 to 9. On one end of each of the arms17 and in the other surface thereof opposite one surface thereofconfronting the corresponding surface of the recording medium of thedisk 13, a tapered surface 17a is arranged as a sloping surface. Theabove tapered surface 17a is formed so that the thickness of each of thepositioners 14 in the direction of lamination of the disks can bedecreased gradually toward the most leading portion of one end of eacharm 17. Further, a base end portion of each reproducing/recordingelement is fixed on the tapered surface 17a. In this case, a taperedangle θ (see FIG. 9) is formed so that it is 5 to 10 degrees to thecorresponding surface of the disk 13.

In the first preferred embodiment and the other embodiments describedhereinafter, typically, an integrated unitary magnetic head 18 shown inFIG. 4 is utilized as the reproducing/recording element (for example,see U.S. Pat. No. 5,041,932, or announcement by Censtor Corporation inData Storage 90 An International Forum; Sep. 10-12, 1990 Fairmont HotelSan Jose, Calif.). Henceforth, the above integrated unitary magnetichead 18 will be described in detail with reference to the relatedfigures. The integrated unitary magnetic head 18 consists of a flexiblethin sheet body 18a, such as a laminated sheet of Aluminium Oxide (Al₂O₃), a head portion 18b that is located on one tip portion of said body18a and has an air gap for reproducing or recording on one surface ofthe body 18a, and a mounting portion 18c formed on the opposite tipportion of the body 18a.

Further, the total weight of the integrated unitary magnetic head 18 isapproximately 1 mg, which is much less than a conventional MIG (metal ingap) magnetic head. In the first preferred embodiment, as shown in FIG.6, it is designed such that the distance t (see FIG. 6) between thesurface of the disk 13 and the surface of the corresponding arm 17 thatconfronts the surface 13 of the disk 13 in a direction of lamination ofthe disk 13 should be 0.3 to 0.6 mm.

Further, it is also designed such that the positioner 14 should beflexible with the range of 0.3 to 0.6 mm in a direction of lamination ofthe disk 13, when the integrated unitary magnetic head 18 is fixed onthe tapered surface 17a.

Further, in the first preferred embodiment, with regard to the methodfor fixing the unitary magnetic head 18, a method utilizing athermohardening adhesive or a method utilizing spot welding by laser orthe like seems reasonable. In this case, the fixing process of theunitary magnetic head 18 is preferably executed by using athermohardening adhesive. To be more concrete, first, the mountingportion 18c is mounted provisionally on the tapered surface 17a of thearm 17 by means of a thermohardening adhesive. Next, after locating theunitary magnetic head 18, the adhesive is heated to the curingtemperature to become sufficiently hard.

Further, the head portion 18a of the unitary magnetic head 18 will bedescribed in more detail with reference to FIG. 8. The above headportion 18a consists of a yoke 18d, a coil 18e wound on the yoke 18d andan air gap 18f formed between both ends of the yoke 18d.

Here, with reference to FIGS. 12 and 13, two methods for laying leadwires of the unitary magnetic head 18 will be described respectively.

In a first example shown in FIG. 12, an FPC (flexible printed circuitboard) 8 is arranged from one tip portion toward the opposite tipportion of one side area on one surface of the arm 17. Further, the leadwires 9 extending from each of the unitary magnetic heads 18 isconnected to one end of the corresponding FPC 8.

In a second example shown in FIG. 13, FPC 8 is arranged from one tipportion toward the opposite tip portion of one central area on onesurface of the arm 17.

Further, lead wires 9 extending from each of the unitary magnetic heads18 are connected to one end of the corresponding FPC 8.

In FIGS. 4 to 11 again, a sequence of operations for the construction ofa disk drive according to the first preferred embodiment will bedescribed. In this case, each disk 13 is driven rotationally by aspindle motor as a disk driving means (not illustrated in thesefigures).

First, when an electric current is supplied to the coil 15, which isarranged inside the magnetic gap of a magnetic circuit 16, a drivingforce is induced in the coil 15 and then each positioner 14 is drivenrotationally for the base 11. Next, each positioner 14 is rotated andtherefore the head portion 18b of the unitary magnetic head 18 gainsaccess to a desired track of the corresponding disk 13 and finally dataread/write operations are performed for the above disk 13.

In such a construction, a suspension element and spacer is notnecessary, which is different from the construction according to a priorart. Further, a mounting portion 18b of an integrated unitary magnetichead 18 of a thin sheet is fixed on a tapered surface 17a. Here, thistapered surface 17a is formed so that the thickness of each positioner14 (or arm 17) in the direction of lamination of disks can be decreasedgradually toward the most leading portion of one end of the positioner14 (or arm 17).

Consequently, it becomes theoretically possible for the distance betweenadjoining disks 13 to be only slightly larger than the thickness of thearm 18. To be more concrete, in the construction according to a priorart, the distance between adjoining disks is approximately 3 mm at themost. On the contrary in the construction according to a first preferredembodiment, the distance between the disks can be reduced to a value assmall as 1.5 to 2.5 mm.

Further, in the prior art, the total weight of the head supportingstructure including a magnetic head, a suspension element, a gimbal anda spacer is approximately 300 mg, whereas, the weight of an integratedmagnetic head can be reduced to a value of approximately 1 mg. Further,owing to the reduction of weight in an integrated unitary magnetic head,the rigidity of the arm 17 can be reduced, which leads to the reductionof the weight of the arm 17. Consequently, the moment of inertia can beremarkably reduced, and the data access at a higher speed can beperformed, compared with a prior art.

FIGS. 14 and 15 are views showing a second preferred embodiment of adisk drive according to the present invention. To be specific, FIG. 14is a top view showing the whole structure of the magnetic disk drive andFIG. 15 is a front view of FIG. 14. Henceforth, any component that isthe same as that mentioned before will be referred to using the samereference number.

As shown in FIGS. 14 and 15, the construction of a disk drive in asecond preferred embodiment is similar to that of a disk drive in afirst preferred embodiment. However, the structure of positioner 24 ofthe second embodiment is different from that of the first embodiment. Tobe more specific, in the first embodiment, the arms 17 of thepositioners 14 and the spacers 19 are laminated alternately and the arms17 are composed of different members from the positioners 14. On thecontrary, in the second embodiment, arm portions 24a functioning as thearms 17 described before are integrated with positioners 14,respectively. In this case, the above arm portions 24a can be fabricatedby means of cutting.

The above second embodiment has the same advantage as the firstembodiment, particularly in that the distance between adjoining diskscan be reduced and the weight of the head supporting member can beremarkably decreased.

FIGS. 16 to 20 are views showing a third preferred embodiment of a diskdrive according to the present invention. To be more specific, FIG. 16is a top view showing the main part of the magnetic disk drive; FIG. 17is a front view of FIG. 16; FIG. 18 is a top view showing the wholestructure of the magnetic disk drive; FIG. 19 is a front view of FIG. 18and FIG. 20 is an enlarged sectional view taken along 20--20 of FIG. 16.

As is apparent from these figures, the structure of positioners 30 ofthe second embodiment is different from that of the first embodiment. Tobe more specific, in FIG. 16 to 20, one end of each of the arms 35 ofthe positioners 30 is divided into two branches, and a first taperedsurface part 33 and second tapered surface part 34 are formed inrespective end positions of the branches, on which said first unitarymagnetic head unit 31 and second unitary magnetic head unit 32 are fixedrespectively, so that said first and second unitary magnetic head units31, 32 can perform read/write operations for the internal peripheralpart and the external peripheral part of the tracks of each disk 13,respectively.

In such a construction, a plurality of unitary magnetic heads can beused simultaneously at each disk, read/write operations can be performedat a higher speed than the conventional disk drive and access time isshortened. In this case, the construction of the first and secondunitary magnetic head units 31, 32 is the same as the unitary magnetichead 18 in the first preferred embodiment.

Further, in FIGS. 16 to 20, the first and second sloping surface parts33, 34 are arranged on two ends of each of the arms 35 formed inbranches and on the other surface of each arm 35 opposite one surfacethereof confronting the corresponding surface of the recording surfaceof the recording medium of the disk 13. In this case, the above firstand second tapered surface parts 33, 34 are formed respectively so that,the thickness of the two branches of each arm 35 in the direction oflamination of the disk 13 can be decreased gradually toward tworespective leading positions of each arm 35.

Further preferably, the above first and second unitary magnetic headunits 31, 32 further have pairs of unitary magnetic head portions,respectively. Namely, four unitary magnetic heads are arranged in eachof the arms of the positioners. In such a construction, the access timeof a whole disk drive is shortened significantly and a memory devicewith an extremely high speed can be attained.

FIGS. 21 and 22 are views showing a fourth preferred embodiment of adisk drive according to the present invention. To be more specific, FIG.21 is a partial sectional view showing the main part of a disk drive andFIG. 22 is a top view of FIG. 21.

As is apparent from FIGS. 21 and 22, the structure of the positioners 40of the fourth embodiment is different from that of the first embodiment.To be more specific, in FIGS. 21 and 22, a tapered surface 41a isarranged on one end of each of the arms 41 of the positioners 40 and onone surface confronting the corresponding surface of the recordingmedium of the disk. Here, this tapered surface 41a is formed so that thethickness of each of the positioners 40 in the direction of laminationof the disks 13 can be increased gradually toward the most leadingposition of one end of each arm 41. Further, a mounting portion 18c ofan integrated unitary magnetic head 18 of a thin sheet is fixed on theabove tapered surface 41a. Further, a hole 41b is formed in each arm 41,to facilitate the fabrication of the tapered surface 41a.

FIG. 23 is a view showing a fifth preferred embodiment of a disk driveaccording to the present invention.

As is apparent from FIG. 23, the structure of the positioners 50 of thefifth embodiment is different from that of the first embodiment. To bemore specific, in FIG. 23, a tapered surface 51b is arranged on an innerwall surface of a cutout groove 51a, which is engraved on one end ofeach of the arms 51 of the positioners 50. In this case, the opening ofthe cutout groove 51a narrows gradually in the sectional area as theopening goes from the inlet to the interior. Further, the mountingportion 18c of each of the integrated unitary magnetic heads 18 is fixedon the corresponding tapered surface 51b.

FIG. 24 is a front view showing a sixth preferred embodiment of a diskdrive according to the present invention.

As is apparent from FIG. 24, the structure of the positioners 61 andunitary magnetic heads 63 of the sixth embodiment are different fromthat of the first embodiment.

To be more specific, in FIG. 24, in each one of the ends of the arms 62of positioners 61 is formed a parallel surface 62a arrangedapproximately parallel to the surface of a recording modium of each disk13.

Further, each of the integrated unitary magnetic heads 63 consists of aflexible thin sheet body 63a, a head portion 63b located on one tipportion of the body 63b and having an air gap for reproducing orrecording on one surface of the body 63b, and a bent-shaped mountingportion 63c formed on the opposite tip portion of the body 63a. Here,the opposite tip portion is bent back against one tip portion of thebody 63a. Further, the bent-shaped mounting portion 63c of each unitarymagnetic head 63 is fixed on the corresponding parallel surface 62a ofeach arm 62.

All of the fourth, fifth and sixth embodiments have the same advantageas the first embodiment in that the distance between adjoining disks canbe reduced by utilizing a given inclination of the magnetic head to thesurface of the disk, and in that the weight of the head supportingmember can be decreased significantly by utilizing an integrated unitarymagnetic head.

FIGS. 25 to 28 are views showing a seventh preferred embodiment of adisk drive according to the present invention. To be more specific, FIG.25 is a simplified front view showing the characteristics of the presentinvention and FIG. 26 is a top view showing the main part of themagnetic disk drive and FIG. 27 is a front view of FIG. 26 and FIG. 28is an enlarged perspective view showing portion C of FIG. 27.

As shown in these figures, a head supporting means 70 is providedbetween each of the unitary magnetic heads 18 and each of the arms 17 ofpositioners 14, which is different from the above mentioned embodiments.

To be more specific, a base end portion of the above head supportingmeans 70 is attached on one end of each of the arms 17 of thepositioners 14. Further, a sloping surface portion 70a that inclinestoward the surface of a recording medium of each of the disks 13 isformed on the tip end portion of each of the head supporting means 70.

In this case, a mounting portion 18c of the integrated unitary magnetichead 18 is constructed to be fixed on the corresponding sloping surfaceportion 70a. Further, the material properties and dimensions of the headsupporting means 70 are selected so that sufficient stiffness for stablysupporting the integrated unitary magnetic head 18 can be ensured.

More concretely, in FIG. 28, when one end of the positioner 14 islocated between adjoining disks 13 having a laminated arrangement, theabove head supporting means 70 includes a first head supporting member70-1 and a second head supporting member 70-2. The above firstsupporting member 70-1 is fixed on one end of each of the arms 17 of thepositioners 14 and the sloping surface portion 70a, which inclinestoward the surface of a recording medium of one of the adjoining disks13. On the contrary, in the second supporting member 70-2, the oppositetip portion thereof is laminated on the opposite tip portion of thefirst supporting member 70-1. Further, the sloping surface portion 70aof the above second supporting means 70-2 inclines toward the surface ofa recording medium of the other adjoining disks 13.

In this case, a pair of unitary magnetic heads 18 are constructed to befixed on the sloping surface portions of the first and second headsupporting members 70-1, 70-2, respectively.

In such a construction, the size of the head supporting means 70 can besufficiently small and therefore the distance between adjoining disks 13becomes much smaller than the prior art, similar to the other preferredembodiment previously described.

Furthermore, in the seventh embodiment, the weight of the headsupporting means 70 can be much smaller than that of the other headsupporting components, such as arms 17, and therefore the total weightof the head supporting structure can be reduced, significantly similarto the other embodiments.

FIGS. 29 to 31 are views showing an eighth preferred embodimentaccording to the present invention. To be more specific, FIG. 29 is atop view showing the main part of the magnetic disk drive. FIG. 30 is afront view of FIG. 29 and FIG. 31 is an enlarged perspective viewshowing portion D of FIG. 30.

As shown in these figures, the configuration of the head supportingmeans of the eighth embodiment is different from that of the seventhembodiment.

To be more specific, when one end of the positioner 14 is locatedbetween adjoining disks 13 having a laminated arrangement, the abovehead supporting means includes a base end portion 80-1, a first slopingsurface part 81 and a second sloping surface part 82. The above base endportion 80-1 is fixed on one end of each of the arms 17 of thepositioners 14.

Further, the first sloping surface part 81 extends from the base endportion 80-1 and inclines toward the surface of a recording medium ofone of the adjoining disks 13.

Further, the second sloping surface part 82 extends from the base endportion and inclines toward the other adjoining disks 13.

In this case, the first sloping surface part 81 and second slopingsurface part 82 are arranged parallel with each other, and a pair ofunitary magnetic heads 18 are constructed to be fixed on the first andsecond sloping surface parts 81, 82, respectively.

Also in such a construction, the distance between adjoining disks 13becomes much smaller than the prior art and the total weight of the headsupporting structure can be reduced, significantly similar to theseventh embodiment. Furthermore in the eighth embodiment, it is notnecessary for the head supporting members to be laminated, which isdifferent from the seventh embodiment. Therefore, it becomes possiblefor the distance between adjoining disks in the eighth embodiment to besmaller than the distance in the seventh embodiment.

FIG. 32 is a view showing a ninth preferred embodiment of a disk driveaccording to the present invention. More specifically, FIG. 32illustrates the whole structure of the magnetic disk drive.

As shown in FIG. 32, the construction of a disk drive in a ninthpreferred embodiment is similar to that of a disk drive in a seventhpreferred embodiment. However, the structure of the positioner 90 of theninth embodiment is different from that of the seventh embodiment. To bemore specific, in the ninth embodiment, the arms 17 of the positioners14 and the spacers 19 (not shown in FIGS. 25 to 28) are laminatedalternately and the arms 17 are composed of different members from thepositioners 14. On the contrary, in the ninth embodiment, arm portions90a functioning as the arm 17, described before, are integrated withpositioners 14, respectively. In this case, the above arm portions 90acan be fabricated by means of cutting, similar to the arm portions 24aof the second embodiment.

The above ninth embodiment has the same advantage as the seventhembodiment, particularly in that the distance between adjoining diskscan be reduced and the weight of the head supporting structure can besignificantly reduced.

FIGS. 33, 34 and 35 are views showing a tenth preferred embodiment of adisk drive according to the present invention. To be more specific, FIG.33 is a top view showing the main part of the magnetic disk drive; FIG.34 is a front view of FIG. 33 and FIG. 35 is an enlarged perspectiveview showing portion E of FIG. 34.

As shown in these figures, the construction of the head supportingstructure in the tenth embodiment is similar to that of the headsupporting structure in the third embodiment (see FIGS. 16 to 20),except that the integrated unitary magnetic head of the tenth embodimentis fixed on one end of the arm 17, via the head supporting means.

In such a construction, the access time of a whole disk drive isshortened and read/write operations can be performed at a higher speed,similar to the third embodiment.

FIGS. 36, 37, 38 and 39 are views showing an example of a disk drivehaving the whole structure in which two disks are assembled in a diskenclosure according to the present invention. To be more specific, FIG.36 is a front sectional view showing the whole structure; FIG. 37 is anexploded perspective view showing the main part of the structure; FIG.38 is a partially assembled perspective view showing the main part ofthe structure and FIG. 39 is an enlarged perspective view showing themain part of the structure.

As shown in these figures, a magnetic disk drive includes the followingcomponents as a whole: two disks having a diameter of less than 1.8inch, a disk driving means that forces the disks to rotate, fourmagnetic heads that perform read/write operations for the surfaces ofrecording media of the disks, arms that support the magnetic heads,positioners that support the arms rotatably, bearings that are arrangedto allow the positioners to rotate, a positioner driving means thatforces the positioners to rotate and make the magnetic heads move to apredetermined position on the surface of recording media of the fixeddisks, a base and cover that constitute a disk enclosure in combinationwith each other; the disk enclosure protecting at least the disks, thedisk driving means, the magnetic head, the arms, the positioners, thebearings and the positioner driving means, and circuits for controllingat least the disk driving means, read/write operations of the magneticheads and the positioner driving means.

In this case, the above circuits are composed of a flexible printedcircuit board to be contained in the disk enclosure, and the height ofthe magnetic disk drive can be less than 10.5 mm. Further, the upperends of shafts 113a, 113b are tightened to the cover 112 with screws.

On one shaft 113a, two magnetic recording media (disks) 128 aresustained and a spindle 120 is assembled. Further, on the other shaft113b, actuators 130 including magnetic heads 135 and arms 134 aresustained. The above actuators 130 are adapted to move and maintain themagnetic heads 135 on the desired track of the disk 128.

115 denotes a flexible printed circuit board. This printed circuit board115 is adhered and fixed to the inner surface of the base 111 and cover112 with a releasable adhesive, etc. On the printed circuit board 115,electronic circuit components 116, which is necessary for controllingthe operation of whole disk drive (for example, servo control unit, DCMcontrol unit, read/write unit, interface control unit and the like), areassembled. Further, the printed circuit board 115 is connected to aconnector that is supported by the base 111 and cover 112. Further, theconnector 117 is connected to the receptacle of external electronicequipment (for example, a portable note-type computer) and therefore themagnetic disk drive shown in FIGS. 36 to 39 operates as a memory deviceof the above external electronic equipment.

Further in these figures, a spindle 120 has an in-spindle constructionin which a hub of a DCM (direct current motor), i.e., the outer diameterof a rotor yoke, is approximately equal to the inner diameter ofmagnetic recording media 128. 121 denotes a stator having laminatedstructure silicon steel sheets. Stator 121 is fixed to the shaft 113a bymeans of adhesion. 122 denotes a coil of copper wire wound around thestator 121. Lead wires (not shown in FIGS. 36 to 39) extending from thecoil 122 are connected to the respectively corresponding terminal on theprinted circuit board 115 by means of soldering and therefore thecurrent for driving the spindle 120 is supplied to the coil 122, via thelead wires.

Further, 123a denotes a rear bearing for magnetic recording media and123b denotes a top bearing therefor. 124 denotes a spacer that maintainsa constant gap between the rear bearing 123a and the top bearing 123b.The inner rings of the rear bearing 123a and the top bearing 123b areadhered and fixed to the shaft 113a. 125 denotes a hub of iron material.The inner peripheral portion of the hub 125 is adhered to the outerrings of the rear bearing 123a and the top bearing 123b.

Further, in the position confronting the stator 121 in the hub 125, amagnet 126 is adhered to the stator 121, concentrically. Consequently, amagnetic circuit is formed by the stator 121, a hub 125 and a magnet126. By supplying an alternating current to the coil 122, a drivingforce is induced in the above magnetic circuit to make the hub 125rotate. Two sheets of magnetic recording media 128 are held between abrim portion of the hub 125 and the spring ring 127, via a first spacering 129a and a second space ring 129b. By fastening the spring ring 127to the hub 125 by compression by means of screws 114, the compressionforce is induced between the brim portion of the hub 125 and the springring 127, thereby firmly fixing two sheets of magnetic recording media128 and the first and second space ring 129a, 129b.

Further, the construction of the actuator 130 including a magnetic head135 and arm 134 will be described in detail, particularly in FIG. 40.131a denotes a rear bearing for an actuator and 131b denotes a topbearing therefor. 132 denotes a spacer that maintains a constant gapbetween the rear bearing 131b and the top bearing 131b. The inner ringsof the rear bearing 131a and the top bearing 131b are adhered and fixedto the shaft 113b. 133 denotes a block of aluminium material. The innerperipheral portion of the block 133 is adhered to the outer rings of therear bearing 131a and the top bearing 131b.

Each brim portion 133a is arranged on one corresponding end of eachblock 133. On the respective surfaces of the brim portions 133a, fourarms are adhered and fixed, respectively. The magnetic recording media128 are adhered to one end of the arms 134, respectively. The magneticbead 135 confronts the respectively corresponding surfaces of themagnetic recording area. The coil 136 is fixed firmly on each side ofthe block 133 opposite each rim portion 133a by resin molding.

140 denotes a magnetic circuit that consists of a magnet 141 and a yokeof iron material 142. The above coil 136 is held in a magnetic air gap143 of the magnetic circuit 140. The coil 136 is connected to thecorresponding terminals on the printed circuit board 115, via aninterconnecting means 116a, (for example, flexible printed circuitboard) and the current is supplied to the coil 136. When the currentflows through the coil 136 located in the magnetic air gap, the drivingforce is induced in the coil 136. Consequently, an actuator 130 movesrotationally around the shaft 113b. In read/write operations, a trackposition signal, indicating the present position of the magnetic head onthe tracks, is issued from the magnetic head. In response to the abovesignal, the control circuit assembled on the printed circuit boardcontrols the current that is supplied to the coil 136 and then moves andmaintains the magnetic recording head 135 on the desired track of eachmagnetic recording medium 128.

In this case, an integrated unitary magnetic head shown in the previousembodiments is preferably used as a magnetic head, to realize smallerdimensions. However, a conventional magnetic head, such as a MIGmagnetic head, can be used instead of the above unitary magnetic head.

In such a construction, a lower end 142 and an upper end 144 of diskenclosure usually have at least partially unoccupied spaces 146, 148respectively, except for the vicinity of the spindle and actuator.Therefore, the various circuits 116 can be assembled on the above spaceand it becomes possible for the space in the disk enclosure to beutilized effectively. Moreover, utilization of the space 149 in the diskenclosure can be realized by arranging the flexible printed circuitboard 116 in a position other than spindle, magnetic head, etc. andassembling the circuits on the above printed circuit.

Conventionally, in 5 inch, 3.5 inch or 2.5 inch magnetic disk drives, adisk enclosure is made of aluminium to lighten said enclosure and therigid printed circuit board is mounted on the bottom surface of a baseof the disk enclosure.

Furthermore, in a disk drive using the disks having a diameter of lessthan 1.8 inch, the major part of various components of the disk drive isfabricated by press forming sheet metal. Therefore, an increase of thetotal weight can be minimized and the disk enclosure having an excellentshield effect and sufficient stiffness can be realized.

Finally, in a disk drive with two disks according to the presentinvention, a height of less than 10.5 mm and a storage capacity ofgreater than 120 MByte can be realized. In this case, the above diskdrive can have the whole dimensions of approximately 3.37 inch×2.13inch×0.41 inch, similar to the conventional disk drive. Further, theabove disk drive can have the total weight of less than 3 ounce.

We claim:
 1. A magnetic disk drive comprising:two disks having adiameter of less than 1.8 inch; a disk driving means that forces saiddisks to rotate; four magnetic heads which perform read/write operationsfor the corresponding surfaces of said disks respectively; arms thatsupport said magnetic heads; positioners that support said armsrotatably; bearings that are arranged to allow said positioners torotate; a positioner driving means that forces said positioners torotate and makes each of said magnetic heads move to a predeterminedposition on the surface of each of said disks; a base and cover forminga disk enclosure in combination with each other, said disk enclosureenclosing said disks, said disk driving means, said magnetic heads, saidarms, said positioners, said bearings and said positioner driving meansin a first space, said disk enclosure further having a second space notincluding said disks, said disk driving means, said magnetic heads, saidarms, said positioners, said bearings and said positioner driving means;and a flexible printed circuit board secured to an inner surface of atleast one of said base and said cover in at least said second space;said flexible printed circuit board including, in said second space,circuits for controlling said disk driving means, read/write operationsof said magnetic heads and said positioner driving means, said printedcircuit board being arranged in portion of said second space which isopposite to at least one said disk, said space including the innersurfaces of said base and said cover and excluding an area occupied byan actuator and a positioner, whereby the entire space in said diskenclosure can be used effectively to reduce the height of said diskenclosure to less than about 10.5 mm.
 2. A magnetic disk drive as setforth in claim 1, wherein said magnetic heads record on said disksperpendicular to said disks, and wherein the storage capacity of saidmagnetic disk drive is greater than 120 MByte.
 3. A magnetic disk driveas set forth in claim 2, wherein at least one first spindle rotatablysupporting said positioners and a second spindle rotatably supportingsaid disk is engaged directly with said base.
 4. A magnetic disk driveas set forth in claim 1, wherein said arms are fabricated by pressworking sheet metal.
 5. A magnetic disk drive as set forth in claim 1,wherein a motor hub is provided as a disk driving means, and said diskis attached to said motor hub.
 6. A magnetic disk drive as set forth inclaim 1, wherein the disk drive has the whole dimensions ofapproximately 3.37 inch×2.13 inch×0.41 inch.
 7. A magnetic disk drive asset forth in claim 1, wherein the disk drive has the total weight ofless than 3 ounces.